DE1442612A1 - Process for the production of metal oxides - Google Patents

Description

DR. F. ZUMSTEIN - DR. E. ASSMANN - DR. R. KOENIQSBERGER

PATENT LAWYERS. ,

HA2612

TELEPHONE: 2234 76

TELEPHONE:, UMPAT CHECK ACCOUNT: MCINOHEN Ö1139

BANK ACCOUNT: BANK H. HOUSES

Be / Li 2/3 /

2/3/1 Cae I + II + IIa

CENTER NATIONAL DE LA RECHlSItCHE SCIEIiTIi ¹ IQUE, Paris (Seine), France

Process for the production of metal oxides

The present invention relates to processes for the production of metal oxides, in particular Metallniis cn oxyden and their solid solutions, the term "mixed metal oxide" or "mixed metallic oxide" is to be understood as a homogeneous phase which has a crystalline, generally defined structure in which the metal ions and the oxygen ions are arranged in a dense network according to the proportions required to neutralize the charges of cations and anions two or more simple or mixed metal oxides are present in varying proportions, these metal oxides having a "common atom" M.

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The Metallmisehoxde in the context of the present invention can e.g. represented by the following general formulas become: GMO

cOq

Vi or in

G the monovalent metal lithium or sodium, J the bivalent metal EIg, Be, IvIn or Go, M is the trivalent metal Al, Ga, Gr, V, In, Fe, and M is tetravalent vanadium

mean.

The invention also relates to the solid solutions, in their composition in varying proportions either two or more simple metal oxides of the formula

^M 2 ° 3

present what solid binary solutions MgO, - M'gO · * »solid ternary solutions M ₂ O, - M ^ O * - M" ₂ 0 ^, quaternary solid solutions M ₂ O, M'pO ^ - M "οΟχ ~ M ¹ "pO ^ or solid solutions of an even higher order, where M, M ¹ , M"<, .. ".," Are selected from the group of trivalent metals given earlier for the definition of M,
or two or more mixed metal oxides of the formula

2 ^pp

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which results in fixed binary solutions belonging to the systems GMO ₂ G "» M0 ₂ , GMO ₂ - GM ¹ O ₂ , GMO ₂ - G «MM) ₂ , where G ¹ and Iff · from the groups of above in the Definition of G and M metals mentioned are selected, as well as solid ternary or quaternary solutions or solutions of an even higher order;

or two or more mixed metal oxides of the formula

which results in fixed binary solutions that lead to the systems J (MO ₂ ) ₂ J (M ¹ O ₂ J ₂ , J (M0 ₂ ) ₂ - J ^f (MO ₂ J ₂ , J (MO ₂ J ₂ - J ¹ ( M ¹ O ₂ J ₂ helped, where J ¹ and lü * are selected from the metals given earlier for the definition of J and M, as well as solid ternary and quaternary solutions or solutions of even higher orders or two mixed metal oxides, one of which is one of the metals Results in cations that can be present in two different oxidation states, which results in solid binary solutions, which in particular

IV
special to the system J ₂ M 0. - JM ₃ O ₄ accessories,

or one or more simple metal oxides and one or more metal mixed oxides, one or more of which belong to the Spinel] © type, which means solid binary solutions, in particular of the type 6 Μ, Ο. - MM ¹ pO. yields where M never occurs nt only in the pentavalent state, but also in the bivalent state _β

The invention also relates to a method of direct manufacture these abovementioned mixed metal oxides and those mentioned

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solid solutions without the intermediate occurrence of simple oxides.iSXÄS3§SSSX5PsaLX ^ If the product is in amorphous form

expedient
results, it is in the end to heat the mixed oxide in order to bring out the crystalline structure. The method consists in that at a temperature of over 200 ⁰ O and preferably

depending on the circumstances

wise less than 550 0 / under an inert atmosphere (eg »argon or nitrogen) or oxidizing atmosphere (ζ, Βο oxygen or air) or reducing atmosphere (z, £. hydrogen) or oxidizing-reducing atmosphere (hydrogen + water vapor in various proportions) those given below crystallized oxalic acid complexes subjected to pyrolysis: either water-soluble complexes of the general formula

[- - ^(C 2 ° 4 ^ m-2 ^nH 2 °

wherein Ϊ is hydrogen or NH.,

J * Mg or Mn,

M, Μ »... JAl, Ga, In, Or, V, Pe ₁ Co, Mn, m the whole number 3 or 4»

χ + y + .c. = 1 and

η is a number between 1 and 10
mean or

1a) (KH ₄ ) ₄ J [M _x M » _y .... (O ₂ O ₄ ) ^ J ₂ which represents a special pail of 1)

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fa * Ο did

2) (NH ₄ ) ₂ G · rM _x M » _y .... (O ₂ O ₄ U ^ηΙί 2 °

where G ', Li or Na,

M, M 'Al, Ga, Gr or V,

χ + y + .... = 1 and η a number between 1 and 10 mean,

where Tj is H, NH ₄ , Li or Na, the other letters have the meanings given earlier and

χ + y + .... = 1 means at least two of the values

ify / 0

4) X _2p Mg - _L , _v ^ 2 ^V 4'2 I p + 1

where ρ is positive or 0 and

X Go * IVO (CnOjr, I * ·,. Λ j ο TTS-acysryvirar j

r 2-r L ² 4'2J where r between 0 and 2 8 &? S $ g ££ $ and X has the meaning given earlier;

or complexes that are sparingly soluble in water and those of the general formula

(° 2 ⁰ 4 ^ 3 '

5) (Z) ₆ MTlI _x M * (° 2 ⁰ 4 ^ 3 ' ^nIi 2 °

correspond to where

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Z is a neutral molecule, namely HK ,, CO (NH ₂ ) ₂ »isthyleneamine or pyridine and the other letters have the meanings given earlier and χ + y + ..ο = 1,

or complex combinations that crystallize together of at least two complexes of the formulas given earlier, in particular of formulas 1) and 5)> are obtained, said complexes or complex combinations in all cases in their crystalline structure on the one hand contain the metals in the proportions that exactly match the composition of the Mixed oxide or the solid desired solution correspond and on the other hand in the above-mentioned pyrolysis or volatile Contain decomposable residues which can supply oxygen to the pyrolysis residue with the exclusion of all outer atoms, whereby the choice of the atmosphere under which the pyrolysis is carried out makes it possible, in certain cases, to proceed from the same Oxalic acid complex, various mixed oxides or various

to obtain solid solutions, depending on whether the metal M is in the mentioned mixed oxide or in the mentioned solid solution is in the 2- or 3-valent oxidation stage »

The above-mentioned process can also include an additional thermal treatment, which consists in raising the pyrolysis residue to higher temperatures. bring "preferably between 800 ° and 12QO ⁰ Gg uxiü although j @ after under an inert or oxidizing atmosphere ued during a conduction time, which as

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_ 7 -

Puncture of the desired degree of crystallization, the fineness of the grain and consequently the desired specific surface that one wants to impart to the end product is chosen o

The above-mentioned complex combinations, which are subjected to pyrolysis according to the process according to the invention, can, starting from their solutions, be obtained in the anhydrous or hydrated crystal state _β ^ j

The mixed oxides and the solid solutions, to which the pyrolysis of the complex combinations mentioned, result with a large specific surface and in a very fine shape Grains with an average dimension below one micron

The invention relates above all to certain applications of Mischoxy.de and the solid solutions mentioned, in particular as catalytic masses or supports for catalysts (especially as oxidation, hydrogenation, dehydrogenation, v / water splitting, dehydrocyclization, Aromatization and polymerization catalysts), as semiconductors, as ferroelectric or ferromagnetic materials and also as special ceramic masses.

The following examples serve to explain the invention in more detail, without restricting them,

In a first group of examples, a number of according to the invention Mixed oxides souie each of their inventive

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mass production process shown «

Example I.

In order to prepare the anhydrous alkali aluminates NaAlO ₂ or LiAlO ₂ , one begins with the preparation of the corresponding complex salt of the formula

Na (NH ₄ I ₂ - [Al (O ₂ O ₄ ) I, 3H ₂ O

Li (HH ₄ ) ₂

which correspond to the general formula 2, using aluminum powder Reacts with an aqueous solution containing oxalic acid, ammonium oxalate and sodium or lithium oxalate, wherein the narrow proportions of aluminum powder and the other reagents correspond to the following equation:

The equation for the lithium complex is analogous.

Evaporation of this solution gives the crystals of Complex salses according to one of the two formulas given above.

Decomposing the crystals thus obtained by passing it, is subjected to a pyrolysis at a temperature between 200 ° and 550 ° under oxy-chief atmosphere, ¹ consists of air, which even after a little child residue of anhydrous

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Lithium or sodium aluminate leads, which is in the form of iiner Granules whose mean dimension is? is below a micron _.

Heating to 800 ⁰ G for about 2 hours causes an increase in the grain dimensions and an improvement in the crystalline order,

Example II

To prepare the alkali chromites NaGrO ₂ and LiGrO ₂ , the corresponding cortiplex salts of the formula are first prepared

ITa (NH ₄ ) ₂ [Cr (G ₂ O ₄ ) J. 3H ₂ O

which correspond to the previously mentioned general formula 2 by allowing ammonium bichromate to act on a mixture of oxalic acid, ammonium oxalate and lithium or sodium oxalate in aqueous solution at room temperature, the proportions of the various components corresponding to the following reaction equation:

(NH ₄ J ₂ Cr ₂ 0 ₇ + 7H ₂ G ₂ 0 ₄ + (NH ₄ J ₂ O ₂ O ₄ H-Na ₂ C ₂ O ₄ - »2Na (NH ₄ J ₂ for ^ O ^ + 6CO ₂ + 7H ₂ O.

The equation is analogous for the lithium complex.

Evaporation of this solution gives crystals of the complex salts according to one of the two formulas given above "

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These crystals are decomposed by subjecting them to pyrolysis at a temperature between 200 and 50 ° C. under a reducing atmosphere consisting of hydrogen, which leads to a sodium chromia or lithium chromium residue. Diesel residue is present in little ordered form and .Indicates very fine grains, whose mean dimension is less than 1 μ actual

By heating to a temperature in the vicinity of 800 ⁰ C for about 10 hrs., The Komabmessungen be increased, and improves the crystalline order of the residue "

Example III

For the production of Alkalivanadit HaVOp or LiYOp one makes first the corresponding dioxalic acid complex salt of the formula

MO (O ₂ O ₄ ) ₂ J. 2H ₂ O

2H ₂ O

which correspond to the second of the two general formula 4 by adding amonium metavanadate in aqueous solution at room temperature can act on a mixture of oxalic acid and lithium or sodium oxalate, the proportions of the various Components of the reaction correspond to the following equation

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for the lithium complex the equation is analogous «

Evaporation of this solution gives crystals of the complex f which corresponds to one of the above formulas

Stan decomposes the crystals thus obtained by pyrolysis at a temperature between 200 and 55C ⁰ C under a reducing atmosphere of hydrogen is z.Be, resulting in a itfickstand of lithium or tfatriumvanadi.t leads, the bit ordered and very fine grain is Λ and whose mean grain size is less than 1 micron.

By heating to a temperature of about 800 ⁰ C for about 10 hrs., The grain size to be enlarged, and the crystalline order is improved.

Example IY

For the production of MagnesiumchroiniTfc MgCr ^ O. put one first the oxalic acid uhiomic acid complex according to the formula

Mg [cr (H ₂ O) ₂ (G ₂ 0 ₄ ) ₂ j ₂ 7H ₂ O

by mixing chromic anhydride with oxalic acid in the presence of magnesia ^ reduced, the proportions of the various Reaction components correspond to the following equation:

2Cr0 ₃ + 7H ₂ C ₂ 0 ₄ + Mg0 - * Mg · ^ iH ₃ O) ₂ Cr (C ₂ O ₄ J ₂ j ₂ +600 ₂ + 3H ₂ 0.

By evaporating the red-violet solution thus obtained, crystals of rose-purple color of the above-mentioned chromic acid are obtained

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oxalatokomplexeso These crystals are very soluble in water, but stable in air. The crystals are decomposed by pyrolysis at a temperature between 200 and 550 0 under a reducing atmosphere, e.g. than 1 micron and the composition of which corresponds to the formula of MagnesiumchromiJfc MgC-r ^ O, enu «■ - ■ _;

By heating to a temperature of about 800 ^° C. for about 4 hours under an inert atmosphere, which Z ₀ B ₀ consists of argon or nitrogen, "one can enlarge the dimensions of the grains and improve the crystalline order of this residue"

Example V "

For the production of magnesium vanadite MgVpö / one puts first the corresponding oxalic acid complex from iOrmel

(NH ₄ ) ₂ Mg-

ago, that of the first of the two general ones mentioned earlier Formula 4 corresponds to one another in an aqueous medium at room temperature ammonium metavanadate, oxalic acid and magnesia converts, where the proportions of the various reaction components correspond to the following equation:

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5H ₂ ö ₂ 0 ₄ + Mg0 · »

A transparent blue solution is obtained, which by evaporation at room temperature under vacuum gives a dark blue solid which is very soluble in water and in air is stable «,

The compound thus obtained is by pyrolysis at a ™

! Temperature between 200 and 55O ⁰ O under a reducing atmosphere, consisting for example of hydrogen, decomposes, which leads to a black, amorphous, in the air oxidizable residue, the composition of which is that of magnesium vanadite »

By heating to a temperature below 800 0, this residue is crystallized and the bpinel structure MgV ₂ O _{4 occurs} .

Example VI

To produce an anhydrous magnesium xerrite MgFe ₂ O, one first sxolds a complex salt of the formula

_% nH ₂ 0

here, which corresponds to the previously mentioned general formula 1, Inaeifl one treats ferric hydroxide with oxalic acid to a solution to obtain, in which one dissolves the magnesia, with the proportions the reaction components are chosen so that they

9 0 9 8 3 6/11 8.0 BADORIQiNAL

correspond to the following chemical formula; ■ 2Pe (OH) - + 6H ₂ C ₂ 0 ₄ + Mg0

Evaporation of this solution gives crystals of the complex

salt of the above formula »\ · -.

The decomposition of these ¹ crystals by pyrolysis at a temperature between 200 and 550 C under an oxidizing atmosphere, which consists of air, leads to a magnesium ferrite of the formula IgIkO ₄ , which results in ^ 'orm of very fine grains whose mean dimensions are smaller than 1 micron is _β

Example TTI; . . . . '

To produce anhydrous cobaluminate CoAl ₂ O ₄ , you first have to provide a complex salt of the formula

her -j, which corresponds to the general formula ■} _{mentioned earlier 9} . in which one lets solutions of trioxalic acid coraplexes of trioxalic acid coraplexes of 3 = valent cobalt on the one hand and aluminum on the other hand crystallize out, the proportions in which the solutions are mixed are selected so that the proportions of cobalt and aluminum correspond to the above formula =>

The thus obtained crystals of the Komplexsalaes be oxidize the Atmosphäreg decomposed by pyrolysis at a temperature between 200 ° and 55O ⁰ G the -eg of air bestehtV, leading to the

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anhydrous cobalt aluminate of the formula OgAIqO, which leads to in ^ 'orm of very fine grains gives their mean dimensions be less than 1 micron.

Example VIII

To produce the mixed oxide LiEe ₁ -Og, the complex salt of the formula is first prepared

Li (NH ₄ ) _u - pfe (C ₂ O ₄ ) ₃ "| ₅ nH ₂ O

by making solutions of trioxalic acid complexes of the formulas

can crystallize out together, the respective proportions of the two complexes being such that the amounts of lithium and iron correspond to the formula of the complex salt. The crystals obtained in this way are decomposed by pyrolysis at a temperature between 200 and 550 G in an oxidizing atmosphere, which consists of air, which leads to a mixed oxide LiFe Oq, which results in the form of very fine grains, the mean dimensions of which are below 1 / i lie _o

Example IX

To produce the nischspinell 00AlCrO ₄ , first

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the complex sal of the formula

Ö ₂ ° 4 ⁾ 3J ^I1H 2 ^O

here, that of the previously mentioned general formula | ₍ corresponds by allowing the solutions of the trijpalemure complexes of chromium, of trivalent cobalt and of aluminum to crystallize together by evaporation, the solutions being mixed in individual proportions so that the respective amounts of cobalt, chromium and aluminum are in the eo obtained mixture correspond to the formula of the above complex alzee.

These crystals are duroh pyrolysis is at a! Temperature between 200 and 55O ⁰ O under öxydieren-the atmosphere, the ouch air, decomposes, resulting in de · fft "chsplnell CoAlCrO _1, resulting in an amorphous state · Naoh further heating at 700 ° the lines of the MioonepinellB appear in the X-ray diagram · The mixed spinel is obtained in the form of very fine grains, the mean dimensions of which are smaller than 1ju ·

In a second group of examples, various fixed solutions according to the invention and the method according to the invention for the production of the same described

Example I.

In order to prepare solid binary solutions of simple metal oxides Or ₂ O and Al ₂ O *, one first prepares the mixed tri-oxalic acid complexes of the formula

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(HH ₄ ) ₃ [Al ₁ Cr ₁ ^ (C ₂ O ₄ ) J. 3H ₂ O

which correspond to the general formula 3 mentioned earlier by adding the simple complexes

(NH ₄ ) ₃ »| 0r (Ö ₂ 0 ₄ ) ₃ · 3H ₂ O

'- 3H ₂ O ₁

which are isomorphic, can crystallize together »

You can change the value of χ in the mixed complexes between 0 and 1 by selecting the respective proportions of the two above-mentioned simple complexes accordingly, making it possible to use solid solutions Cr ₂ O ₃ -Al ₂ O ₃ over the entire range of possible Compositions to be obtained

This, either by cooling or by evaporation of the mixed crystal obtained complexes are decomposed by pyrolysis at a temperature between 200 and 55O ⁰ C under an inert or reducing (hydrogen, nitrogen or argon) atmosphere, resulting in an amorphous residue. The crystallization of the solid solution Cr ₃ O ₃ - Al ₂ O ₃ is achieved by heating to a temperature above 800 ^° C.

Example XI

To produce solid binary solutions of simple metal oxides Cr ₂ O ₃ and V ₂ O ₃ , the mixed ones are first prepared

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Trioxalic acid complexes of the formula

^3H 2 °

which correspond to the above-mentioned general formula 3, by mixing in an inert atmosphere the simple trioxalic acid complexes of ^y chromium and vanadium, which are isomorphic and which have the formula

exhibit, crystallize together »

By choosing the respective proportions of the two simple complexes accordingly, the value of χ in the mixed complex can be varied between 0 and 1, whereby the solid solutions of the oxides Gr ₂ O ₃ - V ₂ O ₃ over the entire range of possible compositions receives. In order to avoid the oxidation of the ήχ & χ trivalent vanadium, it is essential to carry out these operations under an inert atmosphere, which can consist of argon or nitrogen, for example.

This mixed trioxalic acid complex is decomposed at a temperature between 200 and 550 ° under a reducing atmosphere, which consists of hydrogen, for example, which leads to a solid solution of amorphous Cr ₂ O ^ ₅ - ^ ₂ O- ^ ührs the crystalline

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«19 -

attroh afteohlieeeendes heating under an inert or realized Direction "atmosphere to a temperature above 500 ⁰ C erflelt'wTrd. This crystallization is even better if the solid solution contains more Cr ₂ O _3.

Example, "TO :

For the preparation of solid ternary solutions of simple metal oxides Cr ₂ O ,, ^ O * ^^ ^A1 2 ° 3 ^{8, one} first prepares the ge-trioxalic acid complexes of the formula

3H ₂ O

her «dl · correspond to the previously mentioned general formula 3 ·

In the following example, the procedure for the production of the misoh complex with the same atomic quantities of the 3rd ζ Metals specified, but to achieve different proportions of these three metals it is sufficient to use the solutions to mix the respective simple complexes in the correspondingly calculated proportions

First, an aqueous solution of the trioxalic acid complexes of aluminum and vanadium is prepared by reacting aluminum powder with a solution of ammonium mCTavanadate, oxalic acid and ammonium oxalate, the proportions of the various reaction components being selected so that they correspond to the following equations) NH ₄ V0 ₃ + 4H ₂ 0 ₂ 0 ₄ + I (NH ₄ ) ₂ O ₂ O ₄ + Al * -> (NH ₄ J ₃ [Al (C ₂ O ₄ O + (NH ₄ J ₃ .

[v (C ₂ 0 ₄ ) ₃ ] + H _{2 +} 3H ₂ O + CO ₂

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In addition, a solution of the srioxaleic acid complex of Chromium by mixing potassium bend chromate with a solution of oxal « acid and ammonium oxalate react, whereby the different

such elements of this reaction are in close proximity that they

correspond to the following equation »

The two solutions thus obtained are mixed in such proportions as that the respective amounts of chromium, vanadium and aluminum are the same

By evaporation of the resulting solution in vacuo, the mixed Trioxalsäurekomplex of formula I CTJTT ^ Γ! Τ> * V, Δ], (Cl -Ω} I H ^ O

4 3 1 Ί / 3 1/3 1/3 2 4-31 2 '

which results in the form of dark green crystals that are stable in the air.

Decomposing these crystals at a temperature between 200 and 550C under a reducing atmosphere, which consists for example of hydrogen, resulting in a solid, ternary amorphous solution containing oxidizable iste air Further heating in an inert atmosphere at a temperature above 500 ⁰ C leads to the crystallization of these solid solutions. For example, _e provides a heating to TOOO ° C for a period of 10 hours under an argon atmosphere _e a product that is obtained in the form of very fine crystals. The X-ray diagram of this product shows strong lines.

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Example XIII

For the production of solid binary solutions of mixed oxides LiAlOp and LiCrOp are made 2uers ^ <5en mixed trioxalic acid complex the 3? sleeve

here, which corresponds to the previously mentioned general formula 2, by taking in air the simple complexes of the formulas

and

(NH ₄ J ₂ Li / Al (G ₂ O ₄ O 3H ₂ O

which are isomorphic, can crystallize together.

By choosing the amounts of these "two simple complexes" accordingly, the value of χ in the mixed complex can be varied between 0 and 1, whereby solid solutions of the mixed oxides LiAlO ₂ - LiCrOp are obtained over the entire range of possible compositions.

This mixed complex is made by pyrolysis at a temperature between 200 and 550 C under a reducing or inert Atmosphere (hydrogen, nitrogen or argon) decomposes.

The pyrolysis residue crystallizes when heated to a temperature between 600 and 1000 ° e.g. consists of argon or nitrogen.

Temperature between 600 and 1000 ° under an inert atmosphere, the

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Example XIY '. -

For the production of binary solutions of the mixed oxides MgAIpO. and MgCr ₂ O ₄ , the mixed complexes of the formula are prepared first

H ₄ Mg [Al _v Cr ₂ _ _y (G ₂ O ₄ ) ₃ l ₂ ηΗ ,, Ο

here, where η is between 10 and 15, by adding the acidic trioxalate of aluminum and ammonium, the acidic trioxalate of Ammonium and chromium as well as magnesia can react together, with the various reaction components in proportions are present, which are determined according to the chromium or aluminum that one wishes to obtain »If, for example, the mixed complex the same number of aluminum atoms and chromium atoms contains, the reactants are mixed in proportions that correspond to the following equation:

V ₂ (C ₂ O ₄ ) J ₂₊ H ₂ C

Diiareh evaporation of the mixed complex thus obtained in a vacuum Hygroscopic crystals of pink lilac are obtained at room temperature Colour.

These crystals of the mixed complex are decomposed by pyrolysis at a temperature between 200 and 55O ⁰ C under an inert atmosphere (eg, argon or nitrogen) or under a reducing atmosphere (eg, hydrogen), which leads to the fixed binary solution that is a black in the form of amorphous residue results, which by heating to a temperature in

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the order of magnitude of 100O ⁰ C crystallizes, which results in very fine crystals, which correspond to the mixed spinel MgAl ₂ O ₄ -MgCr ₂ O ₄

Example XV

To produce a solid solution of the two spinels 0o, 0 ₄ and CoGr ₂ O ₄ , a complex salt of the formula is first prepared

^nIi 2 °

here, which corresponds to the previously mentioned general formula 3, by allowing solutions of the trioxalic acid complexes of chromium and trivalent cobalt, which are mixed in proportions to obtain the respectively desired amounts of chromium and cobalt, to crystallize together _o

The complex salt thus obtained is then decomposed by pyrolysis at a temperature between 200 and 55O ⁰ C under an oxidizing atmosphere consisting of air, resulting in the above-mentioned solid solution of the two spinels Co ₅ O ₄ and GoGr ₂ O _4. This solid solution results in the form of very fine grains, the mean dimensions of which are less than 1/1.

Example XVI

To produce a solid solution of the following mixed oxides Mg ₂ V ¹⁷ O ₄ and MgV ₂ ¹¹¹ O ₄ ,

which are also known under the name "mixed spinels", and the special characteristic of which is that vanadium is present in

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contains two different levels of oxidation, one sets first the dioxalic acid complex of the formula

Mg VO (C ₂ O ₄ J ₂ I.

which corresponds to the first of the two general formulas 4 mentioned earlier, by simultaneously adding vanadic anhydride, Converting oxalic acid and magnesia in amounts corresponding to the following reaction;

2 Mg / VO (C ₂ O ₄ ) J + 200 ₂ + 5H ₂ 0

₂ 5 ₂

Evaporation of the solution thus obtained under vacuum at room temperature leads to blue, very hygroscopic crystals of the oxalic acid complex of vanadyl and magnesium.

On heating these crystals to 300 to 400 ^ in air it is obtained a residue of magnesium pyrovanadate MgpVpO-y. Heat these crystals to 300 to "400 ° in a reducing atmosphere (Hydrogen) leads to a mixture of magnesium spinel O. and from Magnesia MgO.

On the other hand, the decomposition by pyrolysis of these crystals at a temperature between 200 and 55O ⁰ G under an inert atmosphere, which consists for example of argon or nitrogen, leads to a mixed spinel Mg ₂ VO _{4 and} IvIgV ₂ O ₄ , the crystal order of which can be further heated to higher temperature could improve

Since the mixed metal oxides and the solid solutions of the simple metal oxides or mixed metal oxides with special properties

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shafts, namely their anhydrous state, their reactivity and their specific surface as well as their amorphous or crystallized state, this has numerous advantages over mixed metal oxides and solid solutions the already known connections.

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Claims (1)

~ 26 - U42612 Claims Process for the production of Metalluischoxden and solid solutions, which consist of metal oxides, characterized in that crystallized complex oxalic acid combinations of a pyrolysis at a temperature above 200 O and preferably below 550 O under an inert atmosphere, such as argon or nitrogen, or an oxidizing atmosphere, such as oxygen or air, or a reducing atmosphere, such as hydrogen, or an oxidizing-reducing atmosphere, such as hydrogen plus water vapor, in various proportions _{/ subject} water-soluble complexes corresponding to the following general formulas correspond: Vy ··· (° 2 ^Ο ₄ ) ₃ ] m-2 ^nIi 2 ° where X is hydrogen or NH ,. J; Mg or Mn, M ₁ M ¹ ...! Al, Ga, In, Or, V, Ff ₁ Oo, Mn, m the integer 3 or 4, χ + y + .O ₀ = 1 and
η mean number between 1 and 10, 909836/1 1 80 1U2612 ₂ ηΗ ,, Ο 1a) (HH ₄ J ₄ J IJ ^ Mty ... (O ₂ O ₄ J ₅ ] which represents a special Pall of 1, 2) (NH ₄ ) ₂ G [M _x MIy ... (0 ₂ 0 ₄ ) ₃ ] nHgO where GiLi or Na, M, M ¹ ... ^ Al, Ga, Cr, V, In, Fe, Co , Mn, η a number between 1 and 10 and χ + y + ... = 1 mean, x ^Mt y ··· (° 2 ° 4> 3] ^nIi 2 ° where T'.H, ITH ₄ , Li or Na, the other letters have the meanings given above and is, χ + y + ... = 1 / T'O with at least two of these meanings x, y ... ^ O are 4) X _2p Mg [VO (G ₂ O ₄ ),] _{p + 1} where ρ is positive or means zero and ^X Ar [ ^V0 ί ^σ 2 ° 4> ₂ ] where r is between O and 2 or complexes which are sparingly soluble in water and correspond to the following general formula 5) (Z) ₆ M [M _x M * _y ... (O ₂ O ₄ ) where Z is a neutral molecule, namely NH ,, 00 (ΝΗ ₂ ) _2> Ethylenediaiüin or pyridine and the other letters mean the earlier ones have given meanings and χ + y + ο .. = 1 is _t 909836 / 118Ü UA2612 these complexes in their crystalline structure on the one hand metal in the exact composition of the mixed oxide or have proportions corresponding to the desired solid solution and on the other hand "flattened or GHth (riltGn di θ
decomposable residues in the pyrolysis residue can result in oxygen Si * with the exclusion of all other atoms, the choice of the atmosphere in which the pyrolysis is carried out so that in certain cases, starting from the same oxalic acid complex, different mixed oxides or different solid solutions are formed, whereby the metal M can be in this mixed oxide or in the solid solutions in a bivalent or trivalent oxidation state. 2 · The method according to claim 1, characterized in that complex combinations of .Pyrolyse subjected to common Crystallization of at least two complexes of the formulas 1 to 6, in particular of the formulas 1 and 3, are obtained became" 3 * Method according to claim 1, characterized in that an additional thermal treatment is carried out, which consists ^{in heating the pyrolysis residue to a higher temperature, preferably between 800 and 1200 0} O, under an inert or oxidizing atmosphere, the selected duration being a Function of the degree of crystallization, the grain fineness and accordingly the 909836/1180 1U2612 is the specific surface that one wants to give the final desired product _B 4 · mixed metal oxides and their solid solutions, prepared by the process of claim 1, characterized by the general Formulas GM ₅ O ₈
J (MO ₂ ) G the monovalent metal lithium or sodium, J the divalent metal Mg, Be, Mn or Co, M is a trivalent metal Al, Ga, Or, In, 7, Pe and IV
M tetravalent vanadium mean" ο Fixed binary solutions according to claim 4, produced according to the method of claim 1, characterized by the general formulas GMO ₂ - G «MO ₂ , GMO ₂ - GM ¹ O ₂ , GMO ₂ - G ¹ K * O ₂ and J (MO ₂ ) ₂ - J (M'O ₂ ) ₂ , J (MO ₂ ) ₂ - J '(M0 ₂ ) ₂ , J (MO ₂ ) ₂ - J'iM'Og ^, 6. Solid solutions of simple metal oxides of the formula MpO ^ ₅ (where M denotes the atoms Al, Ga, Gr, V, In or Fe) 909836/1 180 UJ UA2612 according to the method of claim 1, characterized by the general formula u Mo O τ? - M'oO-z ΜΠ - TP ' Ci - IW "* Π 7. Solid solutions consisting of two mixed oxides, in which the one of the metals results in cations which can be present in two different oxidation states, and which after the Process of claim 1, characterized by the formula J. _o M ^IV 0 "- JM ₀ O, '• 2 '4 8c Solid solutions which consist of at least one simple metal oxide and at least one metal oxide, and in which i »- <&& £ bei de» belong to the genus of spinels * and which are produced according to the method of claim 1, characterized by the formula M ₃ O ₄ - MM ^ ₂ O ₄ , where Wi in both bivalent and trivalent Condition is present. 909836/1180